1. Field of the Invention
The present invention relates to an information processing device and a bidirectional transmission method.
2. Description of the Related Art
Most mobile terminals that are typified by mobile telephones and the like use a movable member for a connecting portion between an operation portion that a user operates and a display portion on which information is displayed. Typical examples include the opening and closing structures and the like of folding-type mobile telephones. Furthermore, in addition to telephone functions and e-mail functions, recent mobile telephones are provided with functions for watching and listening to videos, functions for taking photographs, and the like that require the connecting portion described above to be moved in complicated ways according to the user's purpose. For example, in a case where the mobile telephone is used to watch and listen to a video, it is conceivable that the user would want to turn the display portion toward himself and to stow the operation portion, which is not necessary for watching and listening. Thus a structure is required by which the position and orientation of the display portion can be easily changed according to the purpose, such as when the mobile telephone is used as a telephone, when it is used as a digital camera, when it is used as a television receiver, and the like.
However, a large number of signal lines and electric power lines pass through the connecting portion between the operation portion and the display portion. For example, dozens of wires are connected in parallel in the display portion (refer to FIG. 1). Therefore, when a movable member that can be moved in a complicated manner like that described above is used for the connecting portion, the reliability and the like of the wiring diminishes considerably. For this reason, the technology has been shifting from a parallel transmission method to a serial transmission method (refer to FIG. 2) in order to decrease the number of signal lines in the connecting portion. Of course, technological shifts for the same kinds of reasons are not limited to the realm of mobile telephones, but are also occurring in a wide variety of electronic devices for which complicated wiring is required. Note that an additional reason for the shift to serial transmission is to reduce electromagnetic interference (EMI).
In a serial transmission method like that described above, the transmission data is transmitted after being encoded by a specified method. The encoding method that is used may be, for example, the non-return to zero (NRZ) encoding method, the Manchester encoding method, the Alternate Mark Inversion (AMI) encoding method, or the like. For example, in Japanese Patent Application Publication No. JP-A-3-109843, a data transmission technology is disclosed that uses the AMI code, which is a representative example of a bipolar code. In the same document, another technology is disclosed by which a data clock is expressed by an intermediate value of the signal level and transmitted, and the data clock is then regenerated on the receiving side based on the signal level.